The present invention relates to a transport device for a microfilm passage camera. More particularly, it relates to such a transport device for a camera which has a document supply device before a filming station, a device for further transportation of documents in the camera and/or a document discharge device.
Microfilm passage cameras of the above mentioned general type are known by devices used on the market. The principle of the document transportation utilized in these devices includes the use of a plurality of driven endless bands and shafts abutting against the bands. This principle has the disadvantage that a uniform document transporation is not reliably ensured. The mechanical construction required for guidance and for drive of the endless bands, which is surrounded by the bands, requires the complete mounting and disassembly for service. The reasons for a non-uniform document transportation which can lead to a non-sharp filing are the following:
1. The drive shaft diameter changes within the manufacturing tolerances over the length of the drive shaft, PA1 2. The manufacturing tolerances result in differences in the thickness of the bands, PA1 3. The shafts which serve for pressing the documents on the bands extend over the whole document width.
The error causes specified in paragraphs 1 and 2 lead to the speed differences between the bands. The error reason specified in paragraph 3 results in a change in the pressing force between, the bands and the document, and particularly so that in the event of a thickness change of the original, for example a staple of documents, the pressing shaft at this location is lifted and thereby at other locations is either lifted or presses stronger.
As a result, different forces can occur at the locations where the original presses on the bands distributed over the original width. The different pressing forces in connection with the different band speeds lead to the fact that the uniform document transportation in the known microfilm passage devices cannot be guaranteed with sufficient reliability.